title: Quantitative analysis of histidine decarboxylase gene (hdcA) transcription and histamine production by Streptococcus thermophilus PRI60 under conditions relevant to cheese making.
abstract: This study evaluated the influence of parameters relevant for cheese making on histamine formation by Streptococcus thermophilus. Strains possessing a histidine decarboxylase (hdcA) gene represented 6% of the dairy isolates screened. The most histaminogenic, S. thermophilus PRI60, exhibited in skim milk a high basal level of expression of hdcA, upregulation in the presence of free histidine and salt, and repression after thermization. HdcA activity persisted in cell extracts, indicating that histamine might accumulate after cell lysis in cheese.
authors.affiliation: Dipartimento di Biotecnologie, Università degli Studi di Verona, Strada le Grazie 15, 37134 Verona, Italy.
authors.forename: Franca
authors.initials: F
authors.lastname: Rossi
authors.forename: Fausto
authors.initials: F
authors.lastname: Gardini
authors.forename: Lucia
authors.initials: L
authors.lastname: Rizzotti
authors.forename: Federica
authors.initials: F
authors.lastname: La Gioia
authors.forename: Giulia
authors.initials: G
authors.lastname: Tabanelli
authors.forename: Sandra
authors.initials: S
authors.lastname: Torriani
mesh_terms: D000818:Animals; D002611:Cheese / Q000382:microbiology*; D003653:Decarboxylation; D005516:Food Microbiology; D005517:Foodborne Diseases; D006632:Histamine / Q000096:biosynthesis*; D006640:Histidine Decarboxylase / Q000032:analysis / Q000235:genetics* / Q000378:metabolism; D008892:Milk / Q000382:microbiology; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D048249:Streptococcus thermophilus / Q000166:cytology / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic
chemical_list: D006632:Histamine; D006640:Histidine Decarboxylase